Treatment of hydrocarbons



Oct., 25, i938. H. v. ATWELL TREATMENT OF HYDROCARBONS Filed oct. 2s,19a-a INVENTOR. M/MLD l( ATWELL ATTORNEY l Patented Oct. 25,n 1938TREATMENT F HYDROCARBONS Harold V. Atwell, White Plains, N. Y., assignorto Process Management Company, Inc., New York, N. Y., a corporation ofDelaware Application October 26, 1934, Serial No. 750,056

Claims.

This invention relates to the treatment of hydrocarbons of petroleum oranalogous origin, and more particularly to the conversion of gaseousolens to normally liquid hydrocarbons.

It has previously been proposed to subject ole-` nic gases to moderatelyelevated temperatures and high pressures in order to effect thepolymerization of gaseous oleiins to normally liquid low-boilinghydrocarbons suitable for use as motor fuel. The usual source of suchgases comprises the residual gases produced in processes for crackinghydrocarbon oil. Inasmuch as in the oil cracking art the tendency is togo toward more drastic cracking conditions and higher temperatures,favoring the production of relatively large quantities of gases ofrelatively high olefin content in order to obtain high yields of crackeddistillate of relatively high unsaturation, it becomes increasinglydesirable to provide methods for converting as much as possible of thegaseous olens produced in oil-cracking processes to normally liquidlow-boiling products.

. My invention therefore has for an object the provision of a processwherein gaseous oleflns may be more completely and more advantageouslyconverted into normally liquid low-boiling products than has heretoforebeen possible, together with such additional operative improvements andadvantages as may hereinafter be found to obtain.

'I'he polymerization of gaseous oleflns by means of heat and pressurealone,` while advantageous from many standpoints, must under ordinarypractical conditions fail to achieve as complete a conversion of sucholens as would ultimately be desirable. ConsequentlyL the residual gasesfrom such an operation still contain`considerable quantitles of gaseousolefns, although the olen concentration of these residual gases makesthem comparatively unsuitable for further treatment in aheat-and-pressure polymerizing operation.

According to my present invention, residual gases from agas-polymerization operation of the character indicated are subjected toreaction with relatively heavy naphthenic, aromatic or olefinichydrocarbon oils in the presence of suitable cntion operations of thecharacter indicated with oil-cracking and gas-cracking operations in anovel and advantageous manner.

In order that my invention may be clearly set forth and understood, Inow describe, with reference to the accompanying drawing, variouspreferred forms and manners in which my invention may be practiced andembodied.' In this drawing, the single figure is a more or lessdiagrammatic, elevational view of apparatus for carrying out myinvention in a preferred embodiment.

Referring tothe figure, olefinic gasesare introduced by means of a pumpI anda-line 2 into a gas-polymerizing furnace 3 wherein 'the gases areheated to conditions of high pressure and temperature effective to causethe polymerizationl of gaseous olens to normally liquidproducts. Whilethe temperatures and pressures employed may vary considerably as will beappreciated by those skilled in the art,l I have found that temperaturesof from 7009 `to 1100 F. and pressures of from 500 to 3000 pounds ormore are suitable. In the instance illustrated, the products leaving thefurnace 3 are delivered through a transfer line 4 to a soaking zone 5where-they aremaintained for a sufficient period of time to .carry thepolymerization reactions tothe desired extent. The products from thesoaking vessel 5 then pass through a line 6 to a condenser 1, and-themixture of condensate `and residual gas thenxpasses to a high-pressureseparator 8.

Fixed gases comprising largely hydrogen and methane are removed from theseparator 8 through a vent 9 having a valve I0, while condensate passesthrough a line II having a pressure-reducing valve I2l to a low-pressureseparator I3. The gases separated in theseparator I3, of relativelyhigh'olenic concentration as compared to the gases Withdrawn from theseparator 8, pass through a line Il having a valve I5 to a catalyticreaction chamber. I6 -whilethe liquid products of polymerization areremoved from the separator I3 through a yvalvcd line I3'.-

While the use of high-pressure and-low-pressure separators makes itpossible toy achieve a desired separation of hydrogen and methane and towithdraw from lthe polymerization ysystem a gas relatively rich inolef'lns, it will be understood Athat separation of gas and liquids maytake place in a single -stage if desired.

In the present instance, however, the residual gases from the separatorI3, which will ordinarily contain from j10 -to 20% of, oleflnicconstituents but which may contain a higher .or lower percentage ofolei-lns, depending upon the initial concentration of the gases and theextent of polymerization eifected in the furnace 3 and chamber 5, passas aforesaid to the catalytic reaction chamber I 6, where they arecommingled with hydrocarbon liquid containing naphthenic, oleilnic oraromatic constituents, or a mixture of such constituents, introduced tothe chamber I6 through a line I1 having a'pump I8. The catalyticreaction chamber I may be of any convenient type and may be provided, ifdesired, with internal bailies for promoting contact of gases andliquids.

'I'he liquid introduced to the chamber I6 may comprise cycle stock orgas oil or tar producedin the cracking of hydrocarbon oil, or maycomprise tar produced in the cracking of hydrocarbon gases, a line I9being provided for admitting the latter to th\e chamber I5. A suitablecondensing agent, such as aluminum chloride or zinc chloride, or aslurry thereof in oil, is also introduced under suitable pressure to thechamber I5 from a source 20 through a line 2| having a valve 22, theintroduction of the condensing agent being regulated in accordance withthe introduction of the hydrocarbons' to be reacted, for example, in theamount of 5 to 10% of the oil charged.

Within the catalytic reaction chamber I6, the qoleiinic gases andhydrocarbon liquids are caused to react with the condensing agent undersuitable conditions, for example at a temperature of from 100 to 500 F.and under a pressure of from atmospheric to 1000 pounds per square inch.Under the influence of the condensing agent, the reaction is vigorous incharacter and neither high pressures nor long times of contact areordinarily required.

Sludge containing spent catalyst may be withdrawn from the bottom of thechamber I6 through a valved line 23, while the remaining products passthrough a line 24 wherein is 1ocated a pump 25 to a heating coil 25located in a suitable furnace 21. The heat supplied to the products asthey pass through the coil 28 may be merely sufficient to effect avaporization of volatile constituents of these products, for example, byheating the products merely to a temperature below a crackingtemperature, such as 700 F., or, where the nature of the productspermits, they may be carried to a mild cracking temperature of from '750to 850 F. in order to secure a mild cracking or so-calledviscosity-breaking of the products. The heating is ordinarily carriedout vunder a pressure of from 100 to 500 pounds per square inch, so thatupon subsequent release of this pressure an adequate separation ofvolatile and non-volatile constituents may be had.

The heated products then pass through a transfer line 28 having apressure-reducing valve 29 into an evaporator 30 where, under theinfluence of pressure reduction and the heat of the products, avaporization takes place, heavy residual products or tar remaining inliquid form while the lighter and more volatile constituents pass invapor form through a trap-out tray 3I into a fractionating zone 32having suitable plates or trays or other fractionating devices 33 and acooling coil 34. By means of th'e cooling coil 34, or by means of reiluxsupplied to the tower'32 in the well-known manner, a partialcondensation and fractionation is effected, the temperatures ofcondensation lordinarily being such that the liquid material whichcondenses and passes downward through the fractionating column32 and iswithdrawn from the trap-out tray 3I constitutes volatile distillateheavier than gasoline, that is to say, a condensate of the generalnature of gas oil, which is withdrawn from the tray 3l through a line 35having a valve 36.

The heavy residual material which separates in the evaporator 30 may bewithdrawn from the latter through a line 31 having valve 38, or by meansof a line 39 having a valve 40 to be combined with the condensatewithdrawn through the line 35.

Overhead vapors from the fractionating tower 32 pass through a conduit4I to a condenser 42 and a separator 43, from which any light condensateof the nature of gasoline may be withdrawn through a valved line 44while residual gases comprising mainly parailins are withdrawn from theseparator 43 through a line 45.

In the preferred instance, the condensate withdrawn through the line 35,together, if desired, with all or apart of the residue or tar withdrawnfrom the evaporator 30, is subjected to conversion or cracking byintroducing it into a. stream of highly heated gases issuing from afurnace in which paraillnic gases are subjected to high temperatures toeifect their conversion into gaseous oleilns.

Thus, the residual gases from the separator 43 may pass through the line45 wherein is located a pump or compressor 40 to a gas-cracking furnace41. In the preferred instance the gascracking furnace 41 is additionallysupplied with parainic gases either from some outside source through aline 48 having a valve 49 and a pump 50 or through a line 5I whichserves to supply residual gases'from an oil-cracking unit to bedescribed more fully ,hereinbelom Preferably. the gases passing throughthe line 45 into the furnace 41 are subjected at 52 to agas-fractionating operation for the removal of hydrogen and methane.

Inasmuch as gas-fractionating systems for this purpose are known, andsince the details of such fractionation do not constitute a part of thepresent invention, the gas-fractionating stage 52 has been representeddiagrammatically in the drawing. As a preferred ,example of suchfractionation, however, I may employ a gas-fractionating stage wherein asuitable absorption medium, such as liquefied butane, is recirculatedthrough an absorption stage and a stripping stage, the residual gasesbeing withdrawn from the absorption stage Y comprising largely hydrogenand methane, while the gases issuing from the stripping stage containthe higher parafns and oleiins in relatively con-v centrated form.Hydrogen and methane are.

highly heated gases issuing from the gas-cracking furnace 41 passthrough a transfer line 54 having a valve 55 into a reaction chamber 53,and the temperature of the gases is reduced by means of hydrocarbon oilwithdrawn through the lines 35 or 39 or both, which is delivered to thetransfer line 54 through a line 51 having a pump 58 and a valve 59. Theoil withdrawnvthrough the conduit 35 may be used alone for this purposeor it may be combined with the heavier oil withdrawn through the line39, as has been indicated hereinabove. Additional oil, preferably aheavy oil, may be introduced to the transfer line v54, if

Cil

desired, through a line 60having a valve 6I, from any suitable source.In any event, oil is introduced to the transfer line 54 in suchquantities as to reduce the temperature of the admixed gases and liquidto from about 900 to about 1 100 F. In thus cooling the products fromthegas-cracking furnace 41, however,`the oil introduced to the line 54 issubjected for a short period of time to temperatures which may run ashigh as 1400 to 1500 F. and under the influence of such hightemperatures as well as the temperatures prevailing in the reactionchamber 56 the oil is subjected to conversion with resultant productionof additional quantities of gaseous olens. The reaction chamber 56 ispreferably provided with suitable internal bailles 62 for promoting andprolonging contact between the gases and vliquids introduced into thereaction chamber 56. V

Tar or residual liquid produced in the cracking of hydrocarbon gas andoil within the reaction chamber 56 is withdrawn from the latter througha line 6,3 having a valve 64, and is delivered by means of a pump 65either through the line I9 wherein is located a valve 66 to the reactionchamber I6 or may be withdrawn from the system througha branch line 61having a valve 68.

Vapors from the reaction chamber 56 pass through a line 69 to a.fractionating tower 10 having plates or trays 1I and a cooling coil 12.In the fractionating tower 10 the vapors are fractionated to elect thecondensation and separation of distillate heavier than gasoline, i. e.gas oil, this condensate being withdrawn from the bottom ofthefractionating tower 10 to a line 13 having a valve 14 while theremaining vapors pass through a vapor line 15 to a condenser16 and aseparator 11. Lightcondensate or gasoline is withdrawn from theseparator 11 through a valved line 18, while the olefinic gases passthrough a line 19 having a valve 80, to the pump I and line 2 fordelivery into the gas-polymerizing furnace 3.

According to an alternative form of my in` vention, the oil withdrawnfrom the fractionating tower 32 through the line 35 may be subjeoted toconversion in a separate oil-cracking installation.

' In this instance, the tar Withdrawn from the evaporator 30 ispreferably removed from the system through the line 31, and thecondensate withdrawn through the line 35 is delivered by means of thepump 58, the line 51, a branch line 8| having a valve 82 and a line 83to an oilcracking furnace 84. The furnace 84 is also preferably suppliedwith a suitable charging stock, such as gas oil, which is delivered tothe furnace 84 by means of a pump 85 through a heat-exchange coil 86, aline 81 and the line 83. The oil passing through the furnace 84 isheated to a suitable cracking temperature, for example, from 850 to 1050F., under a suitable pressure of from 50 to 1000 pounds per square inch,and then passes through a transfer line 88 having a pressure-reducingvalve 89 into an evaporator 90, from which residual products or tar arewithdrawn through a valved line 9|, While the separated vapors passupward ,through a trap-out dense hydrocarbon vapors heavier thangasoline,

i. e. gas oil, which is withdrawn from the tray 92 through a line 95. Aportion of this gas oil may be returned by means of a line 96 having avalve 91 and a pump 98, the line 81 and the line 83 to the furnace 84,thus providing for recycling this material through the yoil-crackingzone, while a further portion of this gas oil may pass through a branchline 99 having a valve |00 anda line I 0| .wherein is located a pump|02, and the line I1, for delivery into the catalytic reaction chamberI6. Tar withdrawn from the evaporator .90 through the line 9 I may alsobe delivered through a line |03 having a valve |04 tothe pump |02 andthence to the catalytic rcaction chamber I6, or any desired Amixture ofthe gas oil withdrawn at 95, and the tar withdrawn at 9| may bedelivered to the reaction chamber I5.

The overhead vapors from the fractionating tower 93 pass through a line|05 to a condenser |06 and to a gas separator |01 from which lowboilingcracked distillate, i. e. gasoline or naphtha, is withdrawn through avalve line |08. Residual gases, according to their relative concen- Vtrations of olens and paraflins, may pass either through a line |09having a valve IIO and a pump III to the catalytic reaction chamber I6,or may be delivered through the line wherein is located a valve 'I I2and if necessary a pump ||3, to the line 45 which supplies the gascracking furnace 41, preferably first passing through the hydrogen-y andmethane-separator 52.

Instead of introducing the oil withdrawn through the line 35 to theinlet to the furnace a4, this 011 may be delivered by means of ches line51 and a branch conduit I|4 having a valve ||5 to the ,transfer line 89,where it serves as a quenching medium for reducing the temperature ofthe products from the furnace 84. Heavy distillate produced in thegasand oil-cracking operation conducted at 56 and condensed in 10 mayalso be delivered by means of the line 13 and a pump II6 either througha branch line I I1 having a valve II8 to the line 83 for delivery to thefurnace 84, or through a line |9 having a valve |20 to the transfer line88.

It will be apparent from the above that'in my process residual gasesfrom the gas-polymerization operation may be further reacted withhydrocarbon oil and in the presence of a condensing agent to produceliquid reaction products, and such reaction products or ,a portionthereof may be cracked, either in an oil-cracking operation or in agas-cracking operation. In one embodiment described hereinabove,hydrocarbon oil may be cracked to produce motor fuel, heavier voil andresidual gases, the residual gases being subjected to cracking for thepurpose of increasing their oleiinic content and then subjected topolymerization for the purpose of converting gaseous oleiinsto normallyliquid products suitable for leaving residual gases whichmay be furthercracked to produce additional gaseous olefins suitable forpolymerization.

It will further be apparent to those sldlled in .the art that, while Ihave described my invention hereinabove4 with respect to variouspreferred examples and operating details, my invention is not limited tosuch illustrative lexamples or details, but may variously be embodiedand practiced within the scope of the claims hereinafter made.

I claim:

1. The process-of producing low-boiling normally liquid hydrocarbon oilfrom gases containing olens, which comprises subjecting said gases toelevated temperature and high pressure to effect a polymerization of asubstantial portion of said oleiins to normally liquid products,removing normally liquid products of polymerization, subjectingremaining gases to reaction in the presence of a catalytic condensingagent with relatively heavy hydrocarbon oil containing residualconstituents to effect the formation of normally liquid hydrocarbon oilproducts of higher boiling-point range than the desired final product,removing said products, subjecting at least a part of them to conversionat a high cracking temperature to produce-gaseous oleilns and relativelyheavy hydrocarbon oil, separating said last-mentioned oil from otherproducts, supplying it, at least in part, for reaction with saidremaining gases in the Vpresence of said catalytic condensingagent, andrecycling gaseous oleiins thus produced for Fsubjection to said elevatedtemperature and high pressure to eiIect a further polymerization thereofto low-boiling normally liquid hydrocarbon oil.

2. The process of producing low-boiling normally liquid hydrocarbon oilfrom hydrocarbon gases containing gaseous paraiiins which comprisescracking said gases at high temperature to` effect a conversion ofgaseous parains to gaseous oleiins, subjecting resultant oleiinic gasesto elevated temperature and high pressure to eiect a polymerization of asubstantial portion of said olefins to normally liquid products,removing normally liquid products of polymerization, subjectingremaining gases to reaction in the presence of a catalytic condensingagent with relatively heavy hydrocarbon oil containing residualconstituents to effect the formation of normally liquid hydrocarbon oilproducts of higher boiling-point range than the desired ilnal product,removing said products, subjecting at least a part of them to contactwith the highly heated gases leaving the gas-cracking stage for theproduction of gaseous olens and relatively heavy hydrocarbon oil,separating said lastmentioned oil from other products and supplying it,at least in part, for reaction with said remaining gases in the presenceof said catalytic condensing agent. l

3. The process of producing low-boiling normally liquid hydrocarbon oilfrom hydrocarbon gases containing gaseous parafilns which comprisescracking said gases at relatively high temperature and under relativelylow pressure to effect a conversion of gaseous paraiiins to gaseousoleiins, subjecting resultant oleiinic gases to a relativelyv lowtemperature and under a relatively high pressure to effect apolymerization of a substantial portion of said olefins to normallyliquid products7 removing normally liquid products of polvmerization,subjecting remaining gases to reaction in the presence of a catalyticcondensing agent with relatively heavy hydrocarbon oil containingresidual constituents to eiiect the formation of normally liquidhydrocarbon oil products of higher boiling-point range than the desirednal product, removing said products, subjecting at least a part of themto contact with the highly heated gases leaving the gas-cracking stagefor the production of gaseous oleiins and relatively heavy hydrocarbonoil, separating said last-mentioned oil from other products, supplyingit, at least in part, for reaction with said remaining gases in thepresence of said catalytic condensing agent, and returning at least-aportion of the residual gases remaining after reaction with said heavyoil to the gas-cracking stage.

4. The process of producing low-boiling nor-y mally liquid hydrocarbonoil from hydrocarbon gases containing gaseous paraflins which comprisesheating said gases at a temperature of from 1200 to l750 F. to eifect aconversion of gaseous parafiins to gaseous oleiins, subjecting resultantoleiinic gases to a lower temperature and a pressure in excess of 1000pounds per square inch to effect a polymerization of a substantialportion of said olens to normally liquid products, removing normallyliquid products of polymerization, subjecting remaining gases toreaction in the presence of a catalytic condensing agent with relativelyheavy -hydrocarbon oil containing residual constituents to effect theformation of normally liquid hydrocarbon oil products of higherboiling-point range than the desired final product, condensing andremoving said products, .commingling them with the highly heated gasesleaving the gas-cracking stage for the production of gaseous oleiins,separating residual products of the commingled oil and gases prior todelivering the oleiinic gases to the gaspolymerizing stage, and reactingcommingled oil thus separated in the presence of said catalyticcondensing agent.

5. In the conversion of hydrocarbons into hydrocarbons within thegasoline boiling range the improvement which comprises reacting normallygaseous hydrocarbons and normally liquid hydrocarbons in the presence ofa catalytic condensing agent to effect formation of normally liquidhydrocarbons of higher boiling range than gasoline, independentlysubjecting thus-obtained normally liquid hydrocarbons of higher boilingrange than gasoline to conversion into gasoline, heavier hydrocarbons,and normally gaseous hydrocarbons, subjecting normally vgaseoushydrocarbons thus obtained to polymerization to obtain liquid polymersand unconverted gases, and supplying unconverted gases resulting fromsaid polymerization to said reaction stage in the presence of saidcondensing agent.

HAROLD V. ATWELL.

